The Bank of England learned to their cost that you cannot stand in the way of the FX market and now the SNB are trying to hold the EUR/CHF above 1.4320. Have a look at any hourly chart. An 8 pip range for 3 sessions in a row. This is what happened in GBP/DMK back in late 1991 before it collapsed, ever tightening intraday ranges and then when the BoE pulled their bid the pair went into vertical freefall.
This is obviously a different situation but nevertheless if the SNB suddenly disappears, watch out for a big black hole.